Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 242022

Area Forecast Discussion
National Weather Service Duluth MN
322 PM CDT Mon Oct 24 2016

.SHORT TERM...(This evening through Tuesday)
Issued at 322 PM CDT Mon Oct 24 2016

High pressure over the Northland will result in another night of
mostly clear skies and light wind speeds, so it will be another
cold night. The relatively low humidity, with dew point
temperatures in the 20s and low 30s as of this afternoon, suggest
temperatures will plummet after sunset. However, a little
concerned about increasing upper-level cloud cover later in the
night associated with blow off from low pressure and shortwaves in
the western US, which will be moving into the Plains overnight
into Tuesday. Therefore, refrained from the coldest model
guidance. May need to lower temperatures, with an update this
evening, if it looks like it will take longer for the upper-level
cloud cover to spread over the Northland. There be enough
relatively humidity amidst the strong radiational cooling later
tonight, and light enough wind speeds, to result in patchy fog for
the lower-lying areas of northwest Wisconsin and the
Arrowhead and Iron Range.

Otherwise, easterly flow will develop overnight with the passing
high pressure, and the flow will pick up in speed during the day
Tuesday. Increasing cloud cover will limit highs to the middle 40s
to low 50s. Strong east to northeast flow will develop over
western Lake Superior during the afternoon and going into the
evening, in response to the approaching low pressure, and that
wind will translate to the Twin Ports area. There could be gusts
of 20 to 25 mph by the late afternoon.

This area of low pressure will be bringing our next round of rain.
However, it will take some time for the rain to move into our
territory because of the relatively dry east to east-southeast
flow. Some of the rain will go into saturating the atmosphere. It
may reach the far southwest forecast area by evening.

.LONG TERM...(Tuesday night through Monday)
Issued at 322 PM CDT Mon Oct 24 2016

A shortwave trough will dig across the Northern Plains into
northern Minnesota at the beginning of the extended. This feature
will move into the central Great Lakes by Wednesday evening. Still
some differences between the latest guidance, with most notably
the ECMWF coming in with a weaker shortwave. At the surface, this
will develop an area of low pressure across Iowa, which will move
eastward into southern Wisconsin by Wednesday evening. This will
bring rain to much of the Northland Tuesday evening through
Wednesday. Tuesday night lows will generally be in the 30s
throughout the Northland. Highs on Wednesday will top out in the
low to mid 40s.

Rain will taper off across much of the forecast area Wednesday
evening into early Thursday morning. Light precipitation chances
will continue across northern Minnesota and eastern Wisconsin
Wednesday evening into Thursday morning as another shortwave
trough dives southeastward from Saskatchewan into western Lake
Superior. Behind the shortwave, weak high will gradually build
into the area. On the western side of the ridge, will see a
gradual warm up for Thursday and Friday as southwesterly warm
advection occurs at 850 hPa.

Will see another shortwave eject from the Pacific Northwest and
late on Thursday and into the Northern Plains by Friday. The
latest ECMWF again features a more subtle shortwave in comparison
to the GFS/GEM. Will see 850 hPa temps between 0C to +5C, so
expecting mainly rain Friday. As the system exits on Saturday will
see cooler northwest flow bringing -5C to 0C air into the
Northland. With the cool northwest flow behind low, kept some
lingering low chances of light precipitation into Saturday morning
as hinted by the latest GFS. Late in the weekend and early next
week a ridge of high pressure will build into the Northern Plains.
The latest GFS/ECWMF bring another round of warm air advection due
to southwesterly flow at 850 hPa. Once again it appears there will
another brief warm up Sunday/Monday before the next system moves
in on Tuesday.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1235 PM CDT Mon Oct 24 2016

VFR conditions will continue through early this evening across
the area as a surface ridge of high pressure slides eastward. An
area of VFR stratus was found over northwest Ontario and portions
of southeast Manitoba this morning. Some of the higher resolution
models, including the HRRR and NAM, suggest those clouds will move
into the INL vicinity this afternoon and linger into this evening.
Winds will go calm for a time tonight at all terminals before
veering east to southeasterly for Tuesday. With veering winds at
INL, think the stratus will retreat northwestward into northwest
Ontario by 25.10Z. An approaching shortwave trough of low pressure
will bring a high cirrus layer into the area overnight. Meanwhile,
the period of clear skies and calm winds may result in areas of
fog. Should the mid and high clouds arrive earlier, the fog
potential would diminish. As winds over western Lake Superior veer
east and southeasterly after 25.08Z, low-level moisture at HYR and
DLH should increase. Think there is a potential for the
development of an MVFR stratus deck at both terminals, but
confidence is lower at HYR since trajectories required are more
complicated. Stratus deck should advect northeast into the
Arrowhead, eventually reaching HIB and possibly INL Tuesday

Confidence in this forecast package is above average through
25.02Z and average thereafter. Greatest concerns are visibilities
with fog development overnight and timing MVFR stratus


DLH  33  47  38  43 /   0  10  70  70
INL  31  48  37  44 /   0   0  40  60
BRD  35  49  40  45 /   0  50  80  60
HYR  31  50  40  44 /   0  10  80  70
ASX  33  50  38  45 /   0  10  60  70




SHORT TERM...Grochocinski
AVIATION...Huyck is the U.S. government's official web portal to all federal, state and local government web resources and services.